Bipolar junction devices such as bipolar SCRs (BSCRs) and BJTs as electrostatic discharge (ESD) protection structures experience difficulties when required for high speed output circuits, since in the case of high frequency bipolar structures the subcollector is typically heavily doped in order to provide the requisite short rise times. In fact the rise time may be comparable or even smaller than the typical rise time of an electrostatic discharge (ESD) pulse. Thus dynamic coupling cannot be used to turn on the device since the sensitivity of the device to dV/dt results in the device either having too low a turn-on voltage during normal operation or too high a turn-on voltage during ESD events. Therefore the few available DC breakdown blocking junctions that are currently available in supported devices do not adequately accommodate different breakdown voltage requirements.
What is needed is away of tailoring the breakdown voltage to the specific needs.